Llasat-Botija et al. (2026) Storm Gloria (2020): coexisting types of compound flooding in the West Mediterranean Region

Identification

• Journal: Natural hazards and earth system sciences
• Year: 2026
• Date: 2026-09-15
• Authors: Montserrat Llasat-Botija, Raül Marcos-Matamoros, Maria Aguilera Vidal, JOSE ANTONIO JIMENEZ, María Carmen Llasat
• DOI: 10.5194/nhess-26-4429-2026

Research Groups

• GAMA (Department of Applied Physics, Universitat de Barcelona)
• IdRA (Water Research Institute, Universitat de Barcelona)

Short Summary

This study examines the coexisting types of compound flooding in the West Mediterranean Region during Storm Gloria (2020), a paradigmatic example of multivariate, spatially compound, and temporarily compound events. The analysis combines daily precipitation, maximum wind gusts, and significant wave height with municipality-level compensation data to quantify the probability of multivariate and spatially compound events.

Objective

• Investigate the coexistence of different types of compound flood events during Storm Gloria (2020)
• Quantify the probability of multivariate and spatially compound events using a two-sided conditional framework and copula models

Study Configuration

• Spatial Scale: The study area comprises the Spanish Mediterranean coast, including provinces such as Catalonia, Valencia, Murcia, and Andalusia.
• Temporal Scale: The event window is objectively defined from 19 to 25 January 2020.

Methodology and Data

• Models used: Two-sided conditional framework and copula models for multivariate and spatially compound events; empirical estimation for temporarily compound events.
• Data sources: Daily precipitation (P24h) from 662 AEMET rain gauges, maximum wind gusts from 140 AEMET stations, significant wave height (Hs) from SIMAR/CoExMed points.

Main Results

• Storm Gloria was a long-lasting, spatially extensive episode involving interacting hazards such as heavy rainfall, high waves, strong winds, snowfall, hail, and local landslides.
• The event produced exceptionally widespread hydrometeorological conditions across the Spanish Mediterranean coast.
• Clear spatial differences emerge in the relative contribution of each hazard alongshore.

Contributions

• This study demonstrates how different types of compound events can coexist within a single atmospheric episode and presents an integrated framework linking hazard characterisation, joint probability analysis, and observed impacts.
• The results show that accounting for the dependence between hazards substantially reduces the estimated return periods of multivariate and spatially compound compared with an assumption of independence.

Funding

• This research was funded by [insert funding sources, e.g., projects, programs, reference codes].

Citation

@article{LlasatBotija2026Storm,
  author = {Llasat-Botija, Montserrat and Marcos-Matamoros, Raül and Vidal, Maria Aguilera and JIMENEZ, JOSE ANTONIO and Llasat, María Carmen},
  title = {Storm Gloria (2020): coexisting types of compound flooding in the West Mediterranean Region},
  journal = {Natural hazards and earth system sciences},
  year = {2026},
  doi = {10.5194/nhess-26-4429-2026},
  url = {https://doi.org/10.5194/nhess-26-4429-2026}
}